docs: update faq and install guidance

docs/providers/minimax.md

@@ -158,3 +158,24 @@ Use the interactive config wizard to set MiniMax without editing JSON:
 - Update pricing values in `models.json` if you need exact cost tracking.
 - See [/concepts/model-providers](/concepts/model-providers) for provider rules.
 - Use `clawdbot models list` and `clawdbot models set minimax/MiniMax-M2.1` to switch.
+
+## Troubleshooting
+
+### “Unknown model: minimax/MiniMax-M2.1”
+
+This usually means the **MiniMax provider isn’t configured** (no provider entry
+and no MiniMax auth profile/env key found). A fix for this detection is in
+**2026.1.12** (unreleased at the time of writing). Fix by:
+- Upgrading to **2026.1.12** (or run from source `main`), then restarting the gateway.
+- Running `clawdbot configure` and selecting **MiniMax M2.1**, or
+- Adding the `models.providers.minimax` block manually, or
+- Setting `MINIMAX_API_KEY` (or a MiniMax auth profile) so the provider can be injected.
+
+Make sure the model id is **case‑sensitive**:
+- `minimax/MiniMax-M2.1`
+- `minimax/MiniMax-M2.1-lightning`
+
+Then recheck with:
+```bash
+clawdbot models list
+```